Booting Linux Kernel without bootloader

David H. Lynch Jr. dhlii at
Fri Jul 28 18:03:48 EST 2006

Clint Thomas wrote:
> Hey guys,
> I have gone through the Linuxppc embedded and dev lists for
> information related to what I am trying to do, but was unable to find
> exactly what i'm looking for.
> Basically, the system I want linux running on does not require the
> initialization of hardware that U-boot provides, or at least it does
> not need it to boot the linux kernel. I want to load an uncompressed
> linux kernel into memory and start the execution of the kernel,
> without using any kind of bootloader. Is this possible? Or does linux
> need some kind of firmware or other software to tell it to start
> executing? Thanks for any info you might have.

    You system powers on. It starts executing whatever is at the reset
vector, Something has to get you from the ppc powering up and going to
never never land, to starting to execute Linux.
    The steps to get from Power on to booting Linux may not be that
complicated, Much of what needs to be done can likely be included as
part of the code for your board in arch/ppc/boot/simple.
    But something still has to be done.

    In my instance I am dealing with a Xilinx V4 (not an ML403). A small
"monitor" program is automatically loaded as part of the FPGA .bit
image. On power on it starts executing.
    It sets up the CPU, cache, and very minimal hardware configuration,
and then loads Linux out of flash and executes it.
    Linux does not have to have alot setup to boot. But something has to
to some minimal initial setup, get Linux into the memory of your system,
and jump to it.


> Clinton Thomas
> cthomas at
> ------------------------------------------------------------------------
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded at

Dave Lynch 					  	    DLA Systems
Software Development:  				         Embedded Linux
717.627.3770 	       dhlii at
fax: 1.253.369.9244 			           Cell: 1.717.587.7774
Over 25 years' experience in platforms, languages, and technologies too numerous to list.

"Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction."
Albert Einstein

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